I remember playing mahjong in the Windows entertainment pack waaaaay back in the day. After a rough day of 7th grade (I can't believe I typed that) it was always calming to boot up my Windows 98 compatible PC and run some relaxing mahjong on it's 200mhz Pentium II. Such a puzzle is timeless, but Atlus's take on it might make my head hurt.
Mahjong Cub3d (cute) for the 3DS takes the classic tile puzzle into the THIRD DIMENSION!--not only with the 3DS's gimmicky visuals, but also by letting you rotate the puzzle 360 degrees for mind bending possibilities. Of course you can play classic mode, and the top screen makes the tiles so 3-dimensional you can almost feel them...ah well, it's better than clicking a mouse.